Positive rack drive for calculators



Oct. 9, 1962 R. M. LOGIE POSITIVE RACK DRIVE FOR CALCULATORS l t e e h st e e h S 2 On mm 8 5 9 1 4 l b e F d e l 1 F TUE INVENTOR Rl/JZSEZZ M106/! Oct. 9, 1962 R. M. LOGlE POSITIVE RACK DRIVE FOR CALCULATORS 2Sheets-Sheet 2 Filed Feb. 14, 1958 INVENTQR RZ/Iffll M1067! A H ORNEYLUnited States Patent 3 ,057,548 PSSETKVE RAQK RKVE FGR QALCULATQRSRussell M. Logic, Fairfield, Conn, assignor to Sperry Rand Ccrporation,New York, N.Y., a corporation of Delaware Filled sea. 14, 1953,58LNO.715,342 4 Ciairns. (Q5. 235--6il) This invention relates to new anduseful improvements in drive mechanisms and has particular reference toa drive mechanism for reciprocating racks in adding machines and thelike.

Hitherto adding racks have been cyclically released and advanced byspring action until stopped by settable pins which are positioned by keydepression.

An object of the invention is to drive the racks forward and backward ina positive manner so that the use of springs is eliminated.

A further object is to provide a construction which has a much lowerpower requirement.

Still another object is to provide a construction which can be operatedeasily by cams on a continuously revolving cam shaft which can be builtinto various spacings with relatively simple parts.

In brief and general terms, the invention includes a reciprocatingdriving element, a reciprocating driven element, means for selectivelyinterrupting the reciprocation of the driven element and a yieldableconnection between the driving and driven elements to permit the drivingelement to continue its reciprocation even though the reciprocation ofthe driven element is interrupted. The word reciprocation is intended toinclude motion to and fro in an are or in a straight line.

More particularly, the invention includes an oscillating lever which isdriven in constant engagement with a pair of complementary cams on arotating drive shaft. A drive rod is supported from said arm andoscillates therewith. A pair of yieldable spring pressed fingers embracesaid rod. These yieldable fingers are on one end of a driven element orpivoted lever the other end of which is associated with an adding rackslide. The adding rack slide is constructed in the usual manner to beinterrupted in its movement by depressed pins in the usual pin box.Therefore the movement of the adding rack slide is irregular. However,the reciprocation or oscillation of the driving lever is constant. Thestroke of the drive lever is greater than that of the driven lever sothat wherever the driven lever is stopped the connections between thetwo levers yield to permit the driving lever to proceed to the end ofits stroke. On the return of the driving lever the yielding connectionis reestablished and the driven lever is returned to its normal initialposition.

A present preferred form which the invention may assume is illustratedin the drawings, of which FIG. 1 is a side elevation of the mechanism;

FIG. 2 is a partial side elevation of the device with an adding rack inforward stopped position and with the yieldable connection stillengaged;

FIG. 3 is a similar view showing the yieldable connection broken and thedriving element in its foremost position; and

FIG. 4 is a partial plan view of the parts shown in FIG. 3.

Referring now in detail to the present preferred form of the inventionshowin in the drawing, there is a constantly rotating drive shaft 10driven by any suitable source of power (not shown) whenever the power isturned on. There is also a set of the usual keys 11 which, whendepressed, are adapted to set pins 12. in a pin box 13 of a well knowntype.

The slide of one order is shown in the drawings and 3,057,548 FatentedOct. 9, 1962 comprises, a forward portion 14 with an upright heel 15 atthe end thereof. This heel 15 is adapted to abut any one of the pins 12when depressed as shown in FIG. 3, thus stopping the rearward movementof the slide in the usual manner. The rear end of the slide 14 has avertical portion 16 to the upper and lower portions of which areconnected the adding and subtracting racks l7 and 18 by means of pins 19in the slide and slots 20 on the racks. The racks are provided withprojecting ears 21 between which ears and the slide portion 16 springs22 extend as shown.

In order to drive the various parts of this device, th drive shaft 16 isprovided with a pair of fixed complementary cams 23 and 24 which arerespectively and continuously engaged by rollers 25 and 26 mounted onspaced arms 27 and 23 of a driving or Operating cam lever 29 pivoted ata fixed point 3%. The arm 27 is extended forwardly and is forked at 31to embrace 'a drive rod 32. This rod 32 extends across all the orders ofthe machine so as to be embraced by forks of similar arms 27 for theother orders thereof. From a consideration of FIG. 4, it will be seenthat there are two sets of complementary cams and two sets of arms withrollers resting on said cams, the outer end of said arms engaging therespective outer ends of the drive rod 32.

It will be observed that the operation of the drive mechanism thus farexplained will result in the up and down reciprocation of the drive rod32 in a generally vertical direction along a slight arc of travel. Inorder to make this movement effective in driving the slide 14, it is tohe noted that the slide 14 has a roller 33 thereon which is embraced bythe forked lower end 34 of a rack driving lever 35 pivoted on a shaft36. The upper end of this lever 35 is also forked as at 37 to embrace aroller 33 on a dependent ear 39 of a rack 49 which is associated in amanner not shown with the printing wheels of the device. It is clearthat as lever 35 is rocked back and forth the slide 14 is moved forwardand backward.

To examine how the lever 35 is thus rocked it will be noted thatintermediate its ends it has a lateral integral extension 41 on which isfixed a stud 42. On this stud are rotatably mounted two scissor-likefingers 43 and 44. At their upper ends these fingers have cars 45 and 46between which extends a spring 47 which tends normally to pull themtogether in the position shown in FIG. 1. It is noted that these fingershave curved recesses or notches 43 and 49 on adjacent edges which forman embracing seat for the drive rod 32 when the fingers are in theirnormal closed position. The finger 43 is curved and at its end overlapsthe adjacent face of the lower end of the driven lever 35, and in anyposition of this lever the overlap is maintained. The curved finger 44is shorter than the finger 43 and, as shown in FIG. 2, lies in a planeadjacent to that of the finger 43. Straps 50 are provided with endapertures which receive respectively the rod 32 and the shaft 36 of thedriven lever so as to maintain the arcuate travel of the rod 32.

Summarizing the operation of the device, it will be noted that when akey 11 is depressed it moves a pin 12 downwardly in the manner usualwith machines using pin boxes. The lower end of this pin is thusdisposed in the path of the heel 15 of the slide. When, in the usualcourse of operation, the power is then applied, the shaft 10 starts torotate and the cams 23 and 24 will through the rollers 25 and 26 startto reciprocate the drive lever 29. This will cause the drive rod 32 tostart reciprocating from the position shown in FIG. 1, thus rocking thelever 35 and advancing the slide 14 until the heel 15 encounters thelower end of the depressed pin 12 as shown in FIG. 2. The movement ofthe slide has of course also moved the racks l7 and 13 in the usualrnanner and their movement has caused the rotation of the accumulatorwheels (not shown) associated therewith. The drive rod 32 under theimpulse of the cams continues to reciprocate to the end of its strokeand, since the driven lever 35 cannot further reciprocate the rod forcesthe fingers 43 and 44 apart against the action of the spring 47 until itreaches the end of its stroke as shown in FIG. 3 whereupon the camsstart to move the drive rod on its return stroke until it is seatedagain in the curved recesses or seats in the adjacent faces of thefingers 43 and 44, and then restores the lever 35 to normal position.

It will thus be seen that I have provided a simple, efficient andaccurate structure which will reciprocate the racks and associated partsin a positive manner without a material play and without the use of theusual restoring springs.

While the invention herein has been fully shown and described in detailwith respect to one present preferred form which it may assume, it isnot to be limited to the specific form shown since many changes andmodifications may be made in the structure to meet different practicalproblems without departing from the spirit and scope of the invention inits broadest aspects. Hence it is desired to cover any and all forms andmodifications of the invention which may come within the spirit andscope of any one or more of the appended claims. 8

What is claimed is:

1. In a calculating machine, the combination with upper and lowercalculating and printing rack slides movable in opposite directions anda constantly operating drive shaft; of acam lever pivoted at one end,cam means for positively reciprocating the free end of the cam lever, arack drive lever pivoted intermediate its ends for lateral rockingmovement and having a lateral extension, said rack drive lever beingconnected at its opposite ends to said slides for sliding saidcalculating rack and a printing rack in opposite directions, a drive rodcommon to all of said racks and supported in the free end of said camlever for vertical reciprocating movement, a pair of scissor fingersshaped to provide a seat for said drive rod and pivoted to saidextension for rocking said rack drive lever upon movement of said driverod, and means for holding the fingers engaged with said drive rod, saidlast mentioned means yielding for passage of the drive rod between saidfingers when the movement of the calculating slide in one direction isblocked whereby the operating movement of the drive rod and the camlever may continue.

2. In a calculating machine, the combination with plural orders ofaccumulators and calculating rack slides for governing the operation ofsaid orders individually, key controlled settable pins to limit themovement of the rack slides in set position printing racks and aconstantly operating drive shaft; of a cam lever pivoted at one end, cammeans for positively oscillating the free end of the cam lever, a driverod in the free end of said cam lever common to all of said orders ofaccumulators, a rack drive lever for each rack slide pivotedintermediate its ends for lateral rocking movement and having a lateralextension, said rack drive lever being arranged at its opposite ends forsliding a calculating rack and a printing rack in opposite directions, apair of scissor fingers shaped to provide a retaining seat for saiddrive rod and pivoted to said extension for rocking said rack drivelever upon movement of said drive rod, means for holding the fingers inrod retaining position, and said holding means yielding for passage ofsaid rod out of the seat and between the fingers when the movement ofthe corresponding calculator rack slide in one direction is blocked by asettable pin in set position, whereby said drive rod and cam lever maycontinue to one extreme limit of reciprocation.

3. In a calculating machine, a pivoted driving lever,

cam means for moving said lever to impart to a free end of the lever apositive reciprocating motion, a drive rod engaging the free end of saiddriving lever, a pivoted driven lever adapted to be rocked, a pair ofscissor fingers pivotally mounted on the driven lever and embracing thedrive rod therebetween to rock said driven lever by a pull through saidfingers, spring means connected to said fingers to urge them intogripping engagement with said drive rod, and means for interrupting therocking movement of said driven lever, said fingers yielding to pass therod therebetween when the movement of the driven lever is interrupted.4. In a calculating machine, pivoted driving lever means, cam means formoving said lever means to impart to said lever means a reciprocatingmotion, a drive rod engageable with said driving lever means, a pivoteddriven lever adapted to be rocked, a pair of fingers pivotally mountedon the driven lever and embracing the drive rod therebetween to rocksaid driven lever by a pull through said fingers, spring means connectedto said fingers to urge them into gripping engagement with said rod, aslide engagea'ble by said driven lever and moved thereby, in oppositedirections, an upright heel on an end of said slide, a pin box,depressible pins therein, keys to be depressed to move the pins into aposition to be engaged by said heel whereby the motion of the slide in agiven direction may be interrupted, and said fingers yielding theirengagement of the rod to pass the latter therebetween when the movementof the driven lever is interrupted.

References Cited in the file of this patent UNITED STATES PATENTS2,515,692 Boyden et al July 18, 1950 2,666,573 Tenoort Ian. 19, 19542,792,986 Tingley et al May 21, 1957 2,832,531 Chall Apr. 15, 1958

